Scientists Seek Origins Of Obesity In The Womb
She went on to have two daughters, and she may have boosted their chances of avoiding becoming obese, like her two older children are.
Thats the implication of research suggesting that something in an obese womans womb can program her fetus toward becoming a fat child and adult. Its not about simply passing along genes that promote obesity; its some sort of still-mysterious signal.
The idea has only recently entered conversations between doctors and female patients, and scientists are scrambling to track down a biological explanation. That knowledge, in turn, may provide new ways to block obesity from crossing generations.
While theres some disagreement on how important the womb signal is, “the evidence is building and building that it is a substantial issue,” said Dr. Matthew Gillman of Harvard Medical School, who studies prevention of obesity.
Others agree. “I think it could be a hugely significant factor,” said Robert Waterland of the Baylor College of Medicine in Houston, who studies the effect in mice.
Dr. Rudy Leibel, an obesity expert at Columbia University, says he doubts it plays a huge role, but still believes its worth studying. If scientists can uncover its biological underpinnings, he said, they may be able to use that knowledge to prevent or treat obesity from other causes.
Perusse, 39, of Three Rivers, Quebec, knows the effects of being very fat. Before her weight-loss surgery in 1995, she packed 284 pounds on her 5-foot-2 frame. She could not ride a bike or climb stairs to her second-floor home without stopping to rest.
Now, although shes still overweight, those limitations are history, she said through an interpreter.
But her older children struggle with their weight. At 5-foot-3 and 300 pounds, her 22-year-old daughter cant bathe her own two children, Perusse said. Her 16-year-old son weighs 230 pounds and stands 5-foot-6.
They were born before she had the weight-loss surgery. Her two younger daughters, ages 4 and 7, came along afterward. Their weights are normal so far, though Perusse said her older children werent overweight at those ages either.
So shes using diet and exercise to try to protect them against what she called rotten genes, including those from their 400-pound father. She said she isnt optimistic.
But Dr. John Kral of the SUNY Downstate Medical Center in New York says his research suggests that obese women who lose weight before pregnancy may be helping the next generation keep off excess pounds – even if fat-promoting genes run in the family.
In addition, those born afterward showed lower levels of blood fats and indicators of future diabetes.
Kral says families typically dont change lifestyle or diet after surgery, so that doesnt explain the outcome.
Instead, he says, the surgical bypass operation made the womens bodies less efficient at digesting and absorbing food, and lowered levels of sugar and fat in the blood. That, in turn, would reduce the number of calories delivered to the fetus to levels like those provided by a normal-weight mother, he said.
And the womens shedding of pounds before the pregnancy would also help, he said.
While scientists are still trying to explain just how obesity could be transmitted from the womb, it makes sense that a mothers obesity could affect her childrens long-term weight, Waterland said. Cues in early life, including some in the womb, guide the development of a persons brain circuitry for controlling the balance between calories consumed and those burned away, he said. So a signal there could have a long-lasting impact.